alloy design,using second phases

Decker, R. F.

doi:10.1007/bf02644252

Cited by 80 publications

(11 citation statements)

References 49 publications

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“…However, it is apparent from Figs 6 and 7 that annealing at low temperatures after HPT processing leads to the formation of a Cr-rich bcc phase having typical dimensions similar to those of the primary phase which are several tens of nanometers after PDA at 873 K and 400 nm after PDA at 873 K. Therefore, the strengthening is not exclusively explained by precipitation at the grain boundaries. For classical precipitation hardening, the precipitates are situated within the individual grains and remain small compared to the grain size so that they are effective obstacles for dislocation motion as in dispersion hardening [42]. The nano-scale precipitates formed in the matrix grains of the present alloy are consistent with this behavior.…”

Section: Mechanical Properties After Post-deformation Annealingsupporting

confidence: 72%

Effect of annealing on mechanical properties of a nanocrystalline CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

Shahmir

Liu

et al. 2016

Materials Science and Engineering: A

254

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A CoCrFeNiMn high-entropy alloy (HEA) was processed by high-pressure torsion (HPT) under 6.0 GPa pressure up to 10 turns at room temperature. It is shown that there is a gradual evolution in hardness with increasing numbers of turns but full homogeneity is not achieved even after 10 turns. Microhardness measurements reveal that the material reaches a saturation hardness value of ~4.41 GPa and in this condition the microstructure shows exceptional grain refinement with a grain size of ~10 nm. An ultimate strength value of ~1.75 GPa and an elongation to fracture of ~4% were obtained in a sample processed for 5 turns. The nanostructured HEA was subjected to post-deformation annealing (PDA) at 473-1173 K and it is shown that the hardness increases slightly to 773 K due to precipitation and then decreases up to 1173 K due to a combination of recrystallization, grain growth and a dissolution of the precipitates. The formation of brittle precipitates, especially σ-phase, at 873 and 973 K significantly reduces the ductility. Short-term annealing for 10 min at 1073 K prevents grain growth and leads to a combination of high strength and good ductility including an ultimate tensile strength of ~830 MPa and an elongation to failure of ~65%.

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Section: Mechanical Properties After Post-deformation Annealingsupporting

confidence: 72%

Effect of annealing on mechanical properties of a nanocrystalline CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

Shahmir

Liu

et al. 2016

Materials Science and Engineering: A

254

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“…For Ni-base superalloys, the most important attributes that need to be quantified are those which influence the mechanical properties at elevated temperature, solid solution and microstructural strengthening [9]. Microstructural strengthening is largely dependent on the grain size, the size, morphology and distribution of precipitates, which varies according to the particular heat treatment [10].…”

Section: Introductionmentioning

confidence: 99%

Assessment of the effectiveness of transition metal solutes in hardening of Ni solid solutions

Gan

Tin

2010

Materials Science and Engineering: A

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“…Aluminum nitride, which is relatively stable at high temperature NiA1 from a thermodynamic viewpoint [8], and has a low thermal expansion coefficient, can be in situ synthesized by milling in a nitrogen atmosphere during MA. The change of dispersoids is expected not to influence overall mechanical properties, since these depend only on the size and spacing of the particles [10]. In addition to this alloy design philosophy, a solid solution with the addition of Fe and the precipitation of the phase in this material have been considered in order to improve room temperature ductility [9] as well as creep resistance [11 ].…”

Section: Introductionmentioning

confidence: 99%

Processing and properties of mechanically alloyed Ni(Fe)Al-Al2O3-AlN

Choo

Lee

et al. 2000

Metals and Materials

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Ni(Fe)AI powders containing a homogeneous distribution of in-situ formed AIN and A1203 dispersoids were produced by a mechanical alloying process in a controlled atmosphere using a high energy attrition mill. The powders were successfully consolidated by either the hot pressing or hot extrusion process. The phase information investigated by TEM, XRD and a modified TGA analysis reveals that Fe can be soluble up to 19.2% to the NiA1 phase(~) at room temperature after the MA process. Subsequent thermomechanical treatment under specific conditions was tried so as to induce a secondary recrystaltization to improve the high temperature properties. However, no clear evidence of abrupt grain coarsening was obtained, presumably due to the restricted condition for the boundary break-away mechanism in this material. The mechanical properties in terms of strength at room temperature as well as at high temperatures were shown to have improved through the addition of AIN, and room temperature ductility wa~s also shown to have improved by the precipitation of the second phase of c~ in this material.

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alloy design,using second phases

Cited by 80 publications

References 49 publications

Effect of annealing on mechanical properties of a nanocrystalline CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

Effect of annealing on mechanical properties of a nanocrystalline CoCrFeNiMn high-entropy alloy processed by high-pressure torsion

Assessment of the effectiveness of transition metal solutes in hardening of Ni solid solutions

Processing and properties of mechanically alloyed Ni(Fe)Al-Al2O3-AlN

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